This invention relates to compositions which possess unique pigmentary properties. The compositions of this invention consist of a 2,9-dichloroquinacridone of unique polymorphic makeup and of such 2,9-dichloroquinacridone in combination with a molybdate orange pigment.
Quinacridone as a compound had been successfully synthesized in the early nineteen hundreds but it was not until 1955 that a synthesis was developed which would produce quinacridone in a commercially useful pigmentary form. This pioneering work was done by W. S. Struve and is disclosed in U.S. Pat. No. 2,821,529. Following in the wake of Struve have been numerous patents including some which disclose 2,9-dichloroquinacridone such as U.S. Pat. No. 3,157,659 to Deuschel et al. The Deuschel et al. patent discloses various polymorphs of 2,9-dichloroquinacridone but does not teach the specific composition discovered by me. In addition, various methods have been developed to improve the processes for the production of pigmentary quinacridone. Representative of such patents is U.S. Pat. No. 3,030,370 to J. Jackson. With the burgeoning use of synthetic pigmentary materials to color goods of all kinds particularly high temperature plastics and polymers, the demands for more durable and intense as well as lower cost pigments has been ever increasing. The 2,9-dichloroquinacridone which I have discovered adds another chapter to the development of this family of pigments.
The other component of the two component pigment compositions of this invention is a molybdate orange pigment or a silica coated molybdate orange pigment such as is taught in U.S. Pat. Nos. 3,370,971 and 3,369,133 to H. R. Linton and 3,567,477 to J. F. Higgins.